Various cell lines as well as organ and suspension cultures will be inoculated with T. pallidum and followed for intra cellular and extracellular survival and multiplication. Modifications in temperature of incubation, gaseous environment and efforts to neutralize oxygen toxicity with superoxide dismutase will be attempted. Attempt purification of Treponema pallidum by separation of T. pallidum from rabbit host testicular tissue utilizing a Ficoll discontinuous density gradient technique. Analyses and determinations will be undertaken on protein and polysaccharide fractions extracted from the cell wall-cell membrane and cytoplasm of cultured or purified T. pallidum. Both homologous and heterologous relationships will be established.